1. Field of the Invention
This invention relates generally to apparatus for dispensing soluble material into a surrounding body of water. More particularly this invention deals with apparatus that dissolves and dispenses a soluble sanitizing material, preferably calcium hypochlorite, into a body of water, such as a swimming pool utilizing forced circulation.
2. Description of the Prior Art
Chemical feeders, used in previous forced flow or circulation systems, have certain common features. All have typically had a dissolving tank or chamber in which the dissolving of the chemical occurs and a chemical retainer in which the chemical is placed. The dissolving liquid, normally water, is typically fed into the dissolving tank by some control apparatus to ensure the proper amount of chemical dissolved.
Prior equipment, however, normally has suffered from wide fluctuations or variations in the amount of chemical that is dissolved and fed into the water. Most dispensers have utilized a solid chemical that is at least partially immersed in water to effect the dissolution.
Where the chemical is a solid hypochlorite, such as calcium hypochlorite, the solid residue of the chemical has presented either aesthetic or functional problems. When the solid residue has gotten into the forced circulation system, it has resulted in unsightly accumulation on the pool bottom. Build up within the feeder apparatus has resulted in clogging and eventual shutdown of the apparatus. This problem is compounded when larger, commercial pools are treated and larger feeders or dispensers must be used. This clogging also affects the reliability of the feed rate of the chemical into the pools, as well as increasing the frequency of maintenance for these prior feeders.
One particularly successful feeder is that shown in U.S. Pat. No. 4,867,196, issued Sep. 19, 1989 to C. M. Zetena et al, which selects a feed rate by changing the immersion height of the tablets through the use of a movable siphon tube. The feeder has three separate chambers: a discharge chamber, a dissolving chamber and a removable tablet container or hopper. Such units give a reliable feed rate control within a limited range. For a given size the feeding rate has a range determined by the maximum and minimum immersion allowed by the siphon tube and the frequency of immersion. It would be desirable to increase the feed rate range of such units so as to serve larger pools where a wider range of feed rates are needed.
The present invention solves this need by providing an adjustable tablet chamber which can be selectively raised or lowered between two positions to provide an additional range to the feed rate.